#ifndef QUERY_QUERY_BUILDER_HPP
#define QUERY_QUERY_BUILDER_HPP

#include "matador/sql/column.hpp"

#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

namespace matador::sql {

class dialect;

class query_builder
{
private:
  enum class state_t {
    QUERY_INIT,
    QUERY_CREATE,
    QUERY_TABLE,
    QUERY_DROP,
    QUERY_SELECT,
    QUERY_INSERT,
    QUERY_UPDATE,
    QUERY_DELETE,
    QUERY_SET,
    QUERY_FROM,
    QUERY_INTO,
    QUERY_WHERE,
    QUERY_VALUES,
    QUERY_ORDER_BY,
    QUERY_ORDER_DIRECTION,
    QUERY_GROUP_BY,
    QUERY_LIMIT,
    QUERY_FINISH
  };

  enum class command_t {
    UNKNOWN,   /**< Unknown query command */
    CREATE,    /**< Create query command */
    DROP,      /**< Drop query command */
    SELECT,    /**< Select query command */
    INSERT,    /**< Insert query command */
    UPDATE,    /**< Update query command */
    REMOVE     /**< Remove query command */
  };

public:
  explicit query_builder(const dialect &d);

  query_builder& create();
  query_builder& table(const std::string &table, std::initializer_list<column> columns);

  query_builder& select(std::initializer_list<std::string> column_names);

  query_builder& from(const std::string &table, const std::string &as = "");

  std::string compile();

private:
  void transition_to(state_t next);
  void initialize(command_t cmd, state_t state);

private:
  const dialect &dialect_;

  command_t command_{command_t::UNKNOWN};
  state_t state_{state_t::QUERY_INIT};

  std::vector<std::string> query_parts_;

  using query_state_set = std::unordered_set<state_t>;
  using query_state_transition_map = std::unordered_map<state_t, query_state_set>;
  using query_state_to_string_map = std::unordered_map<state_t, std::string>;
  using query_command_to_string_map = std::unordered_map<command_t, std::string>;

  static query_state_transition_map transitions_;
  static query_state_to_string_map state_strings_;
  static query_command_to_string_map command_strings_;
};

}
#endif //QUERY_QUERY_BUILDER_HPP